Like many baby boomers, Bill wants to age well and remain sharp as a tack in his golden years. Bill remembers how his father seemed to lose the ability to use the skills and knowledge he acquired over a lifetime, something medical professionals refer to as “crystallized intelligence.” Realizing that people are living longer than ever before, Bill wants to do whatever he can to preserve his crystallized intelligence as he ages.
Fortunately for Bill and others like him, a new study finds lutein can help preserve brain health and crystallized intelligence in older adults.
About the Aging Population and Lutein
There will be significant growth of the older population in the United States, according to the U.S. Census Bureau, with the number of people over the age of 65 more than doubling from 48 million in 2015 to 96 million in 2060. Successful strategies to promote brain aging are therefore essential to the nation’s public health. Nutrition is a promising strategy to improving brain health, in that current research shows specific nutrients affect brain structure and function. The newest research suggests lutein may have a potent effect on the brain.
Lutein is a carotenoid, a naturally occurring plant pigment, acquired only through diet. This plant pigment gives fruits and vegetables their yellow color. Vegetables, especially leafy green and cruciferous vegetables, such as broccoli, and egg yolks contain lutein.
Lutein belongs in the subclass of xanthophylls, which have polar molecular structures that possess unique membrane properties, such as fluidity, communication between brain cells, ion exchange, diffusion of oxygen, membrane stability, and the prevention of oxidation and inflammation. Like other xanthophylls, lutein accumulates in neural tissue. In fact, lutein accounts for most of the carotenoid accumulation in the human brain, and this high concentration of lutein in the brain may indicate its neuroprotective value.
Lutein accumulates in the brain and embeds in cell membranes. There, lutein protects the neuronal structure and function of brain cells. While lutein is distributed in the gray matter of the brain, researchers have detected its presence in the temporal cortex, the prefrontal cortex, and the hippocampus. Lutein accumulates in the brain over a person’s lifespan and may therefore provide lifelong benefits to brain health.
Lutein levels in blood correlate with brain concentrations of the substance in older adults, which suggests that the blood tests reflect lutein status in the brain. This makes it easier for scientists to measure the relationship between lutein and health.
The Relationship Between Lutein and Brain Health
A new study of older adults, published in Frontiers in Aging Neuroscience, links consumption of lutein with the preservation of crystallized intelligence.
Previous research establishes a strong link between lutein and good health, especially cognitive performance, throughout a person’s lifespan. Lead author of the new study, University of Illinois graduate student Marta Zamroziewicz says, “Research also shows that lutein accumulates in the gray matter of brain regions known to underlie the preservation of cognitive function in healthy brain aging.”
Zamroziewicz and Illinois psychology professor Aron Barbey enrolled 122 healthy participants aged 65 to 75 into the study. Participants solved problems and answered questions on the Wechsler Abbreviated Scale of Intelligence, a standard test of crystallized intelligence. Researchers also drew blood samples from study subjects to measure the amount of lutein in their blood.
The scientists also used magnetic resonance imaging (MRI) to measure the volume of various brain structures in each participant. The researchers focused on one specific area of the temporal cortex, known as the parahippocampal cortex, which is the region of the brain likely involved in the preservation of crystallized intelligence.
Zamroziewicz and Barbey found that participants with high serum lutein levels tended to do better on crystallized intelligence tests. While serum lutein levels reflect only recent dietary intake, blood levels can indicate concentrations of lutein in the brains of older adults to reflect long-term dietary intake. Participants with higher levels of lutein in their blood also tended to have thicker gray matter in the parahippocampal cortex.
“Our analyses revealed that gray-matter volume of the parahippocampal cortex on the right side of the brain accounts for the relationship between lutein and crystallized intelligence,” said Barbey. “This offers the first clue as to which brain regions specifically play a role in the preservation of crystallized intelligence, and how factors such as diet may contribute to that relationship.”
The researchers performed a three-step mediation analysis using multivariate linear regressions to account for age, gender, body mass index (BMI), depression status, education, and income.
While the findings do not explain exactly how lutein improves crystallized intelligence, the researchers did find a link between lutein and crystallized intelligence in the parahippocampal cortex. Scientists do not yet understand exactly how dietary lutein affects brain structure, but it may play an anti-inflammatory role or improve communication between brain cells. The results of the study do add to mounting evidence that suggests certain nutrients can slow age-related cognitive decline by influencing how the brain ages.
There is no recommended daily allowance for lutein, but health experts agree there may be benefit in taking a 10 mg lutein supplement daily. The average American only takes in about 2 mg of lutein a day. A handful of foods contain lutein, but someone like Bill would have to eat an entire cup of cooked spinach or kale each day to get all the lutein one needs for good health.
This study is very good news for Bill and other people who want to maintain brain health and cognitive function as they age. Unlike Bill’s father, who struggled to maintain the vast wealth of knowledge gained over a lifetime, Bill can retain his crystallized intelligence by simply taking lutein. What’s even better for Bill is that he can take lutein in supplement form instead of trying to eat an entire cup of boiled spinach each day. Bill and other people like him can stay sharp well into their golden years.